They are also accused of the attempted murder of Aamir’s parents who had tried to stop their son from being attacked.

Hope and Richards both deny the charges against them.

Mr Justice Royce said the case was one which inevitably gives rise to “strong emotions”.

He told the jury they must stand back and put emotion “to one side”.

Mr Justice Royce also reminded the jury that “speeches are not evidence” and told them that it was “on the evidence” that they decide the case.

Describing the attack on Aamir, he said that on April 11, 2010, the promising teenager was in his house, awaiting the arrival of his Koran teacher, when “two men wearing black balaclavas came to his front door”.

The court heard that when the door was opened, two men burst in and brutally attacked Aamir in front of his parents who “tried to stop the attack to no avail”.

Mr Justice Royce described Aamir, who planned to study law at university, as the “entirely innocent victim” of a killing where the killers got the wrong house.

“It was a terrible killing,” he said.

“Each defendant says the other defendant carried out the killing with another man. It is for you to decide whether these two defendants were there or only one. If only one, which one,” said Mr Justice Royce.

The court also heard that it was the prosecution case that Ben Hope allegedly stabbed Aamir’s mother, Parveen and Jason Richards who allegedly stabbed Aamir’s father, Iqbal.

They also heard that it was the prosecution case that one of the attackers stabbed Aamir while he was on the ground.

“The prosecution say that was Ben Hope,” said Mr Justice Royce.

Earlier in the day David Aubrey QC, defending for Ben Hope, made his closing speech.

In it, he described the account given by co-accused Richards as “absurd and ridiculous”.

“We submit that Ben Hope was absolutely right when he said Mr Richards was something of a fantasist,” said Mr Aubrey.

He also accused Richards of fabricating “an elaborate story”.

The court had previously heard that Richards had said he was not one of two men seen leaving his house in North Road around an hour before Aamir was brutally stabbed. However, Richards, alleged that Hope was one of the men in question.

He also alleged that he saw Hope return with blood on his clothing in the time after Aamir was attacked but told the court that Hope would not tell him what had happened.

Hope had said he was in a “drugs stupor” at North Road home at the relevant time when Aamir was attacked.

He also told the court that he borrowed clothes that day from Richards and left his old ones at Richards’s home.

When asked why, Hope said, when he injected his arm with drugs, it was bleeding and the blood became smeared down him when he had fallen asleep in a stupor.

He told the court that he did not see the clothing again and did not ask what had happened to it.

The court had also heard Hope alleged that, when he and Mr Richards went to Cardiff Addictions Unit the day after Aamir was killed, Mr Richards said "he might have killed someone or words to that effect".

In his closing speech, Mr Aubrey referred to the fact that Hope had fallen into sleeps before where he has burnt himself and not realised it.

“We are not talking about quiet naps, we are talking about a man who falls deeply asleep,” he said.

Referring to the issue of why Hope changed his clothing on the day in question, Mr Aubrey reminded the court that a forensic scientist had said there was evidence of Hope’s blood on a number of his pairs of jeans consistent with a person who has injected himself.

He told the jury that Hope was not there when Aamir and his parents were attacked and the appropriate verdict in his case is “one of not guilty”.

John Charles Rees QC, defending for Richards, finished his closing speech by making what he submitted was “a seminal point”.

He said that Aamir’s father, who had tried to stop his son being attacked, had said he grabbed the attacker’s left hand and this is the hand the knife was in.

Mr Rees said the court had heard the “unchallenged evidence” of Richards that he is right-handed.

He told the jury that the evidence points to “another man”.

Mr Rees had earlier listed 18 other points which he submitted “suggest there was a third man”.

He closed by submitting to the court that Jason Richards is “entitled to be found not guilty”.

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